My refrigerator has been working fine. Now all of a sudden the center mullion that the doors shut against is pretty warm (hot) to the touch. Is there a heat strip in the mullion to prevent the door from freezing the door shut? Is there a sensor that is not working properly?

If it is a Maytag or Whirlpool refrigerator, check the refrigerator light.

That thing hardly does anything except annoy people when it burns out.

It can get so hot in some refrigerators that it melts and warps the plastic shell of the refrigerator. It could be burning through the insulation of the fridge right before it shorts something out or starts a fire.

Refrigerators and fires should be opposites.

If the condenser coils are too close to the wall, the heat that is removed from the fridge circulates around the unit. The outside feels hot because there isn't enough air flow to dissipate it.

That sounds like the blast of hot air from the air conditioner vent when you are walking into a restaurant.

Your refrigerator is working on the exact same concept, but without a vent. If the refrigerator is right up against the wall and there's no air flow, the heat builds up around the fridge.

That probably hurts the refrigerator's energy efficiency, too.

Yes, it does.

I think there's plenty of space around the refrigerator, though.

You ought to clean the refrigerator condenser coils anyway. It will let heat escape from the coils more easily, so the unit won't have to work as hard or as long.

I wonder if the coils might be clogged like my AC's were, once.

They might be, though that would require calling in a repair person. Unless it is the mullion.

I have heard of million and mutton but not mullion. What is that?

The mullion is the narrow section between the freezer and fridge. It is sometimes warmed up to prevent sweating due to condensation as you keep opening the doors.

So that part is normally going to be warm.

But if any other part of the fridge is warm, that's not cool.

it should not be the compressor as the bottom is only not cooling.

Hello Al;

My name is Peter. I am a retired field service refrigeration technician.

All is good. Your Mullion heater snaps back when you open the door because it is spring loaded. When you close the door the springs ensure that the mullion is flush and tight against the front of your unit.
The purpose of the mullion heater is to provide low heat to eliminate any moisture (condensate) created by the warm air in the room.

It means the mullion heater is working. The strip between the doors is called the "Mullion" on "Kitchen Aid" this is part of the refrigeration system. Known as a "Yoder Loop".

This is because the mullion heaters are on. This is a system designed to dry up sweating that occurs on the outside of the box in high humidity. Check to see that all the door seals are tight.

the condensor fan by the compressor is not running. this fan cools the compressor and condensor coils. if it does not run then the mullion (center between frzr and refrigerator side) gets very hot

There is an electric heater in the center which is called a mullion heater. If you have an energy saver switch on your model turn it to the saving position.

The mullion frame stays warm to eliminate sweating during the heat season. This is accomplished by routing the heat removed from the unit by the freon through tubing behind the mullion strip(s). Generally this is experienced as "warm". However, if the unit runs longer than normal in an attempt to pull heat out of the box to satisfy the cold control, these mullions will be HOT to the touch. Basically this serves as an alarm to alert you to a circulation problem. You describe a fan at the bottom right rear as "not working"?
I attempted to locate an answer to resolve the issue for you, but you have not provided me with enough information to access my service database.
Tip: Always provide the complete information provided on the manufacturers product information data tag, located on the unit, and not in the user’s manual. This will help you acquire a more accurate and expeditious response to your complaint.
Below is a link that will help you with parts and diagnostic procedures that are specifically tuned to your manufacturers data plate information.
http://www.repairclinic.com/SmartSearch/smartsearch.aspx

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Thank you,
Dave E. (Illeagle)
"Your satisfaction is my personal reward"

This is called a mullion heater and is perfectly normal as this heater prevents the area between the doors from freezing. No danger at all.

This area is called the mullion and should be a little warm so it doesn't sweat. If it is too hot then two things could be the problem. 1. The condensor is plugged (dirty) and needs to be swept out. 2. The condensor fan motor is not working. This cools the condensor coils and is mounted in the back of the fridge behind the bottom panel.